The field of the invention generally relates to electronic controllers, and more particularly relates to apparatus and method of selecting a particular operating mode of an electronic controller that has been preprogrammed to operate in a plurality of different modes so that the controller can be installed in any one of a plurality of different models or configurations of machines.
As is well known, many manufacturers make a variety of different models or machines. For example, an appliance manufacturer that makes clothes dryers and washers will typically make a variety of different models of each. Some models may be for commercial use, and others may be for residential use. Some models may be large tumbler dryers that operate with gas, and others may be smaller clothes dryers that are electric. Some may be basic models, while others may be top-of-the-line models that have additional features. As is well understood, each of these models or configurations typically has its own unique operating parameters or characteristics. For example, even similar commercial dryers that have the same features may have different temperature regulating set points due to differences in burners, drum sizes, thermistors, or locations of mounting the thermistor. Therefore, each model or configuration may typically require a controller uniquely programmed for its particular features, calibrations, or operating requirements.
As is also well known, it is desirable to have a common controller that can be used in a variety of different models or configurations. With such arrangement, the manufacturer can take advantage of the economy of numbers, and also can reduce the cost and complexity of maintaining manufacturing inventory and spares. In the prior art, controllers have been preprogrammed to operate in a plurality of different modes (i.e. one for each model or configuration of machine in which the controller was to be used), and then the operating mode is selected in accordance with the model in which the controller is installed. One method of selecting the particular operating mode was to mount a dip switch on the circuit board of the controller, and then set the switches to provide the controller with logic signals corresponding to the particular model in which the controller was installed. The controller's operating mode would then be determined in response to the logic signals. Another method of selecting the particular operating mode was to provide the controller with logic signals by connecting or cutting jumper wires on the circuit board. A third prior art method was to use an external connector plug with a preconfigured arrangement of jumper wires corresponding to the particular model, and connect the plug to a dedicated terminal block on the circuit board to route logic signals from the circuit board through the plug to the controller.
The above described mode selection methods had drawbacks during initial manufacture, and also during replacement of failed controllers in the field. First, it takes an assembler/technician time to determine what the dip switch setting should be, what jumper wires should be connected, or what external connector should be used. Second, assembler/technician errors can lead to an incorrect operating mode being selected for a particular model in which the controller is installed. Further, in the case of using external jumpers, a field technician may forget to attach the external connector plug to the new controller circuit board that is being installed.